Method of creating a vacuum.



PATENTED AUG. 6, 1907. P. G. HEWITT.

METHOD OF CREATING A VACUUM.

APPLICATION FILED JULY 1, 1904.

ATTORZEY UNITED STATES "PATENT OFFICE.

PETER COOPER HEWITT, OF NEW YORK, N. Y., ASS'IGNOR TO GOOPER HEWITT ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF CREATING A VACUUM.

Specification of Letters Patent.

Patented Aug. 6, 1907.

Application filed July 1, 1904- Serial No. 214,902.

To all whom it mayconcern:

Be it known that 1, PETER COOPER Hswrrr, a citizen of the United States, and a resident of New York, county of New York, State of New York, have invented certain new and useful Improvements in Methods of Creating 9. Vacuum, of which the following is a specification.

It is known that under normal conditions aluminium or magnesium and mercury do not readily amalgamate, whereas these elements when affected by an electric current under certain conditions readily unite. It is also true of other elements besides aluminium and magnesium that they do not readily amalgamate with mercury except under what may be described as abnormal conditions. At the same time these elements, when present in a vapor device under certain conditions have the property of uniting with gaseous elements which property may be absent under normal conditions.

The present invention is designed to take advantage of this property of amalgamated aluminium or other suitable material, for the purpose of improving the vacuum in an apparatus wherein mercury is normally contained or wherein the presence of mercury would not be injurious to the apparatus during the process of manufacture. I

For convenience, I shall refer only to the employment of aluminium under the conditions named, but other materials may be employed in place of aluminium.

The inventionis especially applicable to the process of exhausting mercury vaporapparatus, whether used for lighting or for any other purpose. It contemplates the use of aluminium or other suitable material placed in contact with the mercury constituting one or more of the electrodes of the apparatus, the said material being practically inert with relation to the gases normally contained in the envelop surrounding the electrode-or electrodes, but being rendered active with respect to such gases when electric current is passed through the envelop so as to cause an amalgamation of the aluminium or other material with the mercury.

It is a fact of observation that the process of amalgamation between mercury and a substance such as alu minium is hastened or facilitated by the passage of an electric current. This is probably due to the chemical activity at what are sometimes called the cathode spots where current passes between the cathode and the intervening space, vapor or vacuum. The cathode spots are the points at which the negative electrode flame appears and when the flame strikes the boundary "surface between the mercury and the imamalgamated material there appears to be a chemical excitation of both materials which facilitates their union in the form of an amalgam. In this way, a considerable portion of the gases which might otherwise be injurious to the action of the apparatus is taken by the amalgamated material or substance and a more perfect vacuum is made than would otherwise be the case.

In carrying out the process of exhaustion any suitable pumping or exhausting means may be employed. I show in the drawing, by way of example, an apparatus which can be utilized for the purposes indicated.

In the drawing, 1 is the envelop or container of a mercury vapor lamp, and 2 and 3 are, respectively, the positive and negative electrodes thereof. The apparatus thus constituted may be exhausted through the exit tube, 4, by any suitable means. When the exhaustion has been carried to any desired degree, the tube 4 may be sealed off in the usual way. 4

In the mercury constituting the negative electrode 3,

I may placea piece, 5, of aluminium or other suitable on, electric current is caused to pass through the envelop between the electrodes 2 and 3. Owing to the passage of current as described, an amalgamation takes place between the'mercury 3 and the aluminium or other material 5, whereupon the said material'is brought into a condition in which it readily unites with the elements of the injurious gases inthe container, thereby improving the vacuum in the apparatus. Any appropriate way of securing an amalgamation between the elements 5 and 3 may be employed in place of that described herein.

I claim as my invention:-

1. The method of creating a high vacuum in an inclosed chamber containing mercury and also containing a material which is incapable in its natural state of combining with the gases within the chamber, which consists in exhausting the chamber by any approved process and afterwards nmalgamating the described material, thereby producing a change of condition in said material such that it will absorb or combine with all or a portion of the gases within the chamber.

2. The method of creating a. high vacuum in an lnclosed chamber containing mercury and also containing a maierial which is incapable in its natural state of combining with the gases within the chamber, which consists in exhausting the chamber by any approved process, sealing 3. In a vapor apparatus provided with a negative elecj trode of conducting liquid material and with a solid wetted material in a dliferent plane from the general surface of the liquid, but in contact therewith, the method of render-ing the said solid material elfective for localizing the entrance of current into the negative electrode, which con 1 slate in removing from the surface of the solid material the air or gases which accumulate thereon. 4. In a vapor electric apparatus provided with a negative electrode of conducting liquid material with a solid -wetted material in a different plane from the general surface of the liquid, but in contact therewith, the method of rendering the said solid material effective for localizing the entrance of current into the negative electrode. which consists in throwing the said material into an active state, and absorbing by means thereof the air or gases which accumulate on the surface of the said solid material.

5; In a vapor apparatus provided with a negative electrode of mercury and with a solid material adapted to he wetted by the mercury and being in a different plane from the general surface of the mercury but in contact therewith, the method of rendering the said solid material effective for localizing the entrance of current into the negative electrode, which consists in amalgamating with the mercury of the negative electrode an absorbent material, and thereby causing to be absorbed the film or coating which accumulates on the surface of the said solid material.

6. In a vapor apparatus provided with a negative electrode of conducting liquid material and with a solidwetted material in a diEerent plane from the general surface of the liquid, but in contact therewith, the method of rendering the said solidmaterial eifective for localizing the entrance of current into the negative electrode, which consists in removing from the surface of the solid material the film 'or coating of gas which acccumulates thereon.

Signed at New York, in the county of New York, and State of New York, this 24th day of June A. D. 1904.

PETER COOPER HEWITT.

'Witnesses:

WM. H. CAPEL, GEORGE H. STOCKBRIDGE. 

